A 2,2′-bipyridine derivative works as a chelating ligand for various type of metals, and it readily forms various metal complexes. The thus formed metal complex is useful in industry since oxidation-reduction potential, molecular orbital, and the like can be readily adjusted by introducing an adequate substituent on the bipyridine ring. Among such metal complexes, a transition metal complex having 2,2′-bipyridine derivative ligand can be used for various applications. For example, Japanese Patent Application Laid-Open No. 2007-304091 discloses a gene detection method using electrochemical activity of a ruthenium complex and an osmium complex. Japanese Patent No. 3731752 discloses that a ruthenium complex can be used for a dye sensitized solar battery, and that carboxyl group at the terminal will be immobilized on a porous membrane by forming a chemical bond with the titanium oxide particle, and absorb visible light in substantially all visible range at high conversion rate. Japanese Patent Application Laid-Open No. 2001-64641 discloses use of a ruthenium complex for a luminescent material. Japanese Patent Application Laid-Open No. 9-234374 discloses that ruthenium complex and manganese complex can be used as an oxidation catalyst, and Japanese Patent Application Laid-Open No. 6-247880 discloses that use of complexes of iron, cobalt, ruthenium, and the like as a catalyst for cyclization and dimerization of a conjugated diolefin.
More specifically, in the Examples of the Japanese Patent Application Laid-Open No. 6-247880, the reaction is allowed to proceed in a homogeneous system by using 0.5% by mole of the transition metal complex catalyst with respect to 1 mole of the reaction substrate. Since the transition metal complex is generally expensive, it would be preferable from the industrial point of view to collect the catalyst after the reaction for reuse. When the transition metal complex is used by preliminarily immobilizing the transition metal complex to an inorganic solid such as silica gel or alumina or an organic polymer, the transition metal complex can be readily separated after the reaction for its reuse. The transition metal complex can be loaded on such solid support by using a ligand having a reactive group capable of firmly bonding to the support. An example of such reactive group is silyl group, and silyl group can react with various types of substituents such as hydroxy group on the support. For example, Tetrahedon Letters, 1998, vol. 39, pp. 4359-4362 describes immobilization of ruthenium bipyridine complex on montmorillonite by using silyl group for use as an oxidation catalyst.
However, the ligand used in Tetrahedon Letters, 1998, vol. 39, pp. 4359-4362 is bipyridine substituted at position 6 with silyl group, and formation of bis(bipyridine) complex and tris(bipyridine) complex as described in Japanese Patent Application Laid-Open No. 2007-304091, Japanese Patent No. 3731752, or Japanese Patent Application Laid-Open No. 2001-64641 by using such ligand has been difficult due to steric hindrance by the substituent at the position 6. In view of such situation, development of a new ligand which enables immobilization of various transition metal complexes on the solid support has been highly awaited. In the case of the Japanese Patent No. 3731752, electronic interaction between the transition metal complex and the solid support used for immobilization is utilized. Therefore, a ligand which enables immobilization of the transition metal complex at a distance closer to the support has been desired.